Influence of filler dispersion and interfacial resistance on thermal conductivity of polypropylene/carbon nanotubes systems

Abstract

AC electrical conductivity, shielding effectiveness and viscoelastic characteristics of nanocomposites based on RTV silicon rubber and nano graphite sheets/carbon black hybrid system AIP Conference Proceedings 1914, 030013 (2017) Composites and Biomaterials, National Research Council, Via Campi Flegrei 34, 80078 Pozzuoli, Naples, Italy Carbon nanotubes effectiveness, as thermally conductor, in polymer/CNTs nanocomposites, is mainly related to various key aspects as dispersion, matrix/CNT interfacial resistance and inter-CNT contact resistance. Features of raw materials and processing parameters for the realization of nanotube/polymer composites, can simultaneously affect these critical issues, also in adverse way. In this contribution, polypropylene based-composites, containing multi walled carbon nanotubes (MWNTs), are prepared by melt-blending and then characterized prevalently in term of thermal transport behavior, choosing different matrix grades, filler functionalization and process conditions. In more details, two commercial polypropylene (PP) grades with different melt flow rates are considered as matrices and three kind of MWNTs with the same aspect ratio, one neat and two chemically modified with carboxyl -COOH and amino -NH 2 groups, respectively, are used as fillers. The presence of a compatibilizer, as maleic anhydride grafted polypropylene (Ma-g-PP), and the use of various processing conditions as temperature, time, screw speed, pressure, filler drying and so on, are taken into account in order to optimize the thermal conductivity enhancement of PP/MWNTs compounds.

Thermal Conductivity of Polypropylene-Based Materials

“…Compatibilized samples sometimes display slightly lower TC with respect to noncompatibilized systems, probably due to a polymeric wrapping around particles that hinders the direct contact among themselves and, as a consequence, the thermal transmission [62]. Patti et al [63] found that the addition of PP-g-MA significantly reduced the contribution of included CNTs to the ultimate thermal transport properties of the corresponded mixtures, from +42.2 to +19.6% in presence of neat CNTs and from +47.7 to +11.7% for systems containing amino functionalized CNTs.…”

Comparative Rheological Investigation of Nanocomposites of Surface Charged Superparamagnetic Iron Oxide Nanoparticles with Polyethylene Glycol

“…There are several techniques for the improvement of the quality of filler dispersions in these nanocomposites such as intercalation of polymers from solution, in situ intercalation, or melt intercalation [20][21][22]. The quality of filler dispersions can also be improved with the use of compatibilizers [23][24][25], nanofiller surface treatments [26][27][28] or the application of an electric field to clay nanocomposites [29][30].…”